The present invention relates to cable-end connector. More particularly this invention concerns cable-end connector that incorporates at least one active circuit element, e.g. a printed-circuit board carrying a light-emitting diode.
The end of a multiconductor cable connected to, for instance, a proximity detector is fitted to a connector that itself is adapted to mate with a standardized plug or fit in a standardized socket. The individual conductors of the cable are connected electrically to respective contacts in the body of the connector.
In many applications, for instance the above-cited proximity detector or local-area-network wiring, it is useful to provide the cable-end connector with some active circuit elements that monitor electrical activity in the cable and even provide some indication of such activity. Thus a tiny circuit board carrying various active elements is mounted in the cable-end connector and a window is provided so that a light-emitting diode (LED) on the circuit board can provide a visual indication of line activity.
German patent 4,222,685 of G. Wehrle described a prior-art system where the conductors of the cable are soldered to contacts that themselves are fitted in and soldered to a printed circuit board that is imbedded beneath a clear plastic resin in the body of the connector. This patent document also describes a system where the contacts are tubular and have ends each formed with a stepped notch. A wider outer end of each notch is slightly narrower than the overall width of the respective wire and the narrower inner end is slightly narrower than the diameter of the respective conductor. Thus to make the connection the unstripped end of each wire of the multiconductor cable is shoved down into the respective contact and then bent over and fitted to the respective notch. Then the notched end is fitted tightly into a hole of a circuit board, thereby forcing the respective wire down so that the respective notch cuts through the wire""s insulation and the sides of the narrow inner portion of the notch come into solid electrical contact with the contact.
While this latter arrangement avoids the complexity of having to make two solder joints for each conductor, it still represents a relatively complex system. Installation is somewhat laborious, requiring each conductor to be fitted in place and then bent over individually.
It is therefore an object of the present invention to provide an improved cable-end connector.
Another object is the provision of such an improved cable-end connector which overcomes the above-given disadvantages, that is which is extremely easy and simple to put together, yet which forms a solid electrical and mechanical connection between each conductor and the respective contact and with the printed-circuit board.
These objects are attained according to the invention in an electrical connector used in combination with an electrical circuit board having an active element and formed with a row of throughgoing contact holes and a multiconductor cable having a plurality of wires each having a core conductor. The connector has according to the invention a dielectric body formed with a row of parallel and outwardly open contact seats, a row of parallel and outwardly open wire seats aligned with and extending transversely across the contact seats, and an outwardly open pocket traversed by the contact seats and dimensioned to hold the circuit board with its holes aligned with the contact seats. Respective contacts in the contact seats each have a pointed tip engaged through the respective hole of the board in the seat and poking in the respective wire seat into the respective wire and into contact with the conductor thereof.
The assembly of this connector is extremely simple. The conductors are pushed all the way into their seats and the circuit board all the way into its pocket, then the contacts are pressed into place. As each contact moves into its end position its tip passes through the respective hole in the circuit board, locking the board in place, then pierces into the respective wire, locking the wire in place and making a good electrical connection with the wire""s conductor. The contacts can be premounted in a position not extending into the board pocket or conductor seats, so that once the board and conductors are in place, they need merely be pushed home to complete the assembly.
The circuit-board holes are conductively lined and the contacts have portions adjacent their tips in electrical contact with the respective holes. Thus once the contacts are pushed home, they make the necessary connection between the circuit board and the conductor also. Of course some of the holes can be unlined so that the respective contacts only are connected to one of the conductors. The contact portions are widened and bear laterally elastically on the respective lined holes, something made easy by splitting and spreading the sheet metal forming the contacts.
The body in accordance with the invention has a connector part formed with the contact seats and a grip part formed with the pocket and conductor seats. In addition it is formed with a large-diameter seat dimensioned to loosely receive the cable and into which the conductor seats open. The conductor seats have outwardly flared ends at the large-diameter seat. This makes fitting the wires into the conductor seats easy.
A mass of thermoplastic fills the pocket around the circuit board. The cable is imbedded in the mass also. In fact the mass fills the enlarged seat around the cable to provide strain relief. When the active element is an LED, the mass is at least limitedly transparent. Thus the LED can be seen to monitor, for instance, operation of a sensor connected to the cable.